The presence of biological material in various parts of the human body can lead to complications ranging from artery disease, heart attack, stroke and in some cases death. The safe and effective destruction of the biological material that causes these complications is an important endeavor in the medical field. A variety of prior art instruments and methods destroy biological material in the human body.
Prior art medical instruments used to destroy biological material in the body suffer from several limitations. Prior art medical instruments are large, making it difficult for medical professionals to utilize them. Prior art medical instruments utilize high power levels that can adversely affect areas surrounding the treatment area and the patient. Procedures using prior art medical instruments are time consuming in comparison with other methods such as surgical excision.
Prior art medical instruments have relied on longitudinal vibrations of the tip of the instrument. By creating longitudinal vibrations of the tip, the tip of the prior art medical instrument must contact the biological material and, similar to a jackhammer, remove the biological material through successive motion of the tip of the instrument. In many cases, the prior art instruments operating in a longitudinal mode have a tip having both a small cross sectional area and a small surface area, thereby removing small amounts of biological material and increasing the overall time of the medical procedure.
For example, U.S. Pat. No. 4,961,424 to Kubota et al. discloses an ultrasonic treatment device operating in a longitudinal mode that is urged or brought into contact with an area to be treated, with energy delivered to the tip of the device. U.S. Pat. No. 4,870,953 to DonMicheal et al. discloses an intravascular ultrasonic catheter/probe and method for treating intravascular blockage that delivers ultrasonic energy via a bulbous tip of the instrument where the bulbous tip is placed in contact with a blockage. U.S. Pat. No. 5,391,144 to Sakurai et al. discloses an ultrasonic treatment apparatus that includes an instrument operating in a longitudinal mode that emulsifies tissue at the tip of the instrument. Therefore, there remains a need in the art for a device that can safely and effectively destroy a large area of biological material in a time efficient manner.
Torsional mode vibration of objects is known in the art. However, the prior art does not describe the torsional mode vibration of a medical device. Further, the prior art requires additional objects to be attached to the prior art instruments, thereby preventing a minimally invasive solution of destroying biological material using torsional mode vibration. For example, U.S. Pat. No. 4,771,202 and U.S. Pat. No. 4,498,025 both to Takahashi disclose a tuning fork using the fundamental vibration of a flexural mode coupled with the fundamental mode of torsion. The fundamental frequency of the torsional mode is adjusted by placing masses near the side edges of the tine tips. U.S. Pat. No. 4,652,786 to Mishiro discloses a torsional vibration apparatus having a plurality of electrodes formed on the two surfaces of a circular member of electrostrictive material. Therefore, there remains a need in the art for an apparatus and a method of destroying biological material that utilizes a medical device that can vibrate in a torsional mode to destroy the biological material in the body in a time efficient manner.
The prior art does not provide a solution for destroying biological material in a safe, effective and time efficient manner. The prior art does not provide an effective solution for increasing a surface area for biological material destruction. Prior art ultrasonic instruments are limited in that they require contact between the device and the biological material and only treat the biological material using the tip of the ultrasonic instrument. Therefore, there remains a need in the art for an apparatus and a method for an ultrasonic medical device operating in a torsional mode and a transverse mode to ablate biological material in a safe, effective and time efficient manner.